1. Field of the Invention
The present invention relates to device and method for driving a plasma display panel, and more particularly to device and method for driving a plasma display panel, which permits fast addressing, and minimizes power consumption.
2. Background of the Related Art
The plasma display panel (hereafter called as ‘PDP’) is a display using a visible light emitted from a fluorescent material excited by a UV ray generated by gaseous discharge. The PDP has advantages in that the PDP is thinner and lighter than a cathode ray tube (CRT) that has been major displaying means up to now, and facilitates a large sized high resolution picture.
FIG. 1 illustrates a perspective view of a discharge cell of a related art 3 polar AC surface discharge type PDP.
Referring to FIG. 1, the discharge cell is provided with scanning/sustaining electrodes 12Y and common sustaining electrode 12Z on a bottom of an upper substrate 10, and an address electrode 20X formed on a lower substrate 18 perpendicular to the scanning/sustaining electrodes 12Y and common sustaining electrode 12Z.
There are an upper dielectric layer 14 and a protection film 16 stacked under the scanning/sustaining electrodes 12Y and common sustaining electrode 12Z formed parallel to each other of the upper substrate 10. The upper dielectric layer 14 accumulates wall charges generated at a time of plasma discharge, and the protection film 16 formed of, in general, MgO prevents the upper dielectric layer 14 suffering from damage caused by sputtering of the plasma discharge, and enhances a secondary electron emission efficiency.
There are a lower dielectric layer 22, a barrier 24 on the lower substrate 18 having the address electrode 20X formed thereon, and there is the fluorescent material 26 coated on surfaces of the lower dielectric layer 22 and the barrier 24. The barrier 24 is parallel to the address electrode 20X for preventing the UV ray and the visible light from leaking to adjacent discharge cells, and the fluorescent material 26 is excited by the UV ray emitted at the time of plasma discharge, to emit one of visible lights of red, green, and blue. There is an inert gas injected in a discharge space between the barriers for gaseous discharge.
FIG. 2 illustrates electrode arrangement of a PDP having the discharge cell in FIG. 1.
Referring to FIG. 2, the discharge cells, arranged in a form of a matrix, are formed at crossing parts of scanning/sustaining electrode lines Y1–Ym, common sustaining electrode lines Z1–Zm, and address electrode lines X1–Xn.
A PDP driving device for driving the discharge cells is provided with a scanning/sustaining electrode driving part for driving the scanning/sustaining electrode lines Y1–Ym, a common sustaining electrode driving part for driving the common sustaining electrode lines Z1–Zm, and an address electrode driving part for driving the address electrode lines X1–Xn.
The scanning/sustaining electrode lines Y1–Ym are driven progressively, the common sustaining electrode lines Z1–Zm are driven in common, and the address electrode lines X1–Xn are driven divided into odd numbered lines and even numbered lines.
The 3 polar AC surface discharge type PDP divides one frame into a plurality of sub-fields having different number of discharges for expressing gray levels of a picture. For an example, when it is intended to display a picture of 256 gray levels by using 8 bit video data, one frame period (about 16.7msec) corresponding to 1/60 seconds is divided into 8 sub-fields (SF1–SF8) as shown in FIG. 3.
Each of the 8 sub-fields (SF1–SF8) is divided into a reset period, an address period, and a sustain period, wherein while the reset period and the address period are identical for all the sub-fields, the sustain period increases at a ratio of 1:2:4:8: . . . 128 for the sub-fields. The reset period is a period for initializing the discharge cell, the address period is a period for scanning whole screen progressively and writing a data, and the sustain period is a period for sustaining light emitting states of the cells having the data written thereon.
FIG. 4 illustrates waveforms of a related art method for driving a PDP.
Referring to FIG. 4, after all the discharge cells are initialized by discharge in the reset period (not shown), scanning pulses SP are applied to the scanning/sustaining electrode lines Y1–Ym progressively in the address period, and data pulses DP synchronous to the scanning pulses SP are supplied to the address electrode lines X1–Xn.
In this instance, the common sustaining electrode lines Z1–Zm have a preset level of DC voltage supplied thereto, for stable causing stable address discharge between the address electrode lines X1–Xn and scanning/sustain electrode lines Y1–Ym.
Then, in the sustain period, the scanning/sustain electrode lines Y1–Ym and the common sustaining electrode lines Z1–Zm have sustain pulses SUSPy and SUSPz supplied thereto alternately, for light emission of the discharge cells selected during the address period.
However, if the address period is prolonged, the sustain period becomes very short to drop a luminance in a high definition PDP that has an increased number of scanning/sustain electrode lines Y.
If widths of the scanning pulses and the data pulses are reduced for making the address period short, there can be miss-writing and mal-discharge because an adequate discharge current can not flow to the scanning/sustain electrode lines Y1–Ym the scanning pulses are applied thereto.
In order to solve such a problem, a driving waveform is suggested, which uses the address driving part for generating main data pulses and supplementary data pulses. A related art driving waveform in FIG. 5 will be explained.
When a main data pulse MDP is applied to a plurality of adjacent discharge cells, one supplementary data pulse ADP having a width Tad smaller than a width Td of the main data pulse MDP is applied to parts between the main data pulses MDP as shown in FIG. 5 ‘A’. When any one of the discharge cells has the main data pulse applied thereto, the supplementary data pulses ADP are applied to parts in front and rear of the main data pulse MDP as shown in FIG. 5 ‘B’ and ‘C’. When no main data pulse is applied to the discharge cell, no supplementary data pulse ADP is applied.
The scanning pulse Vs progressively applied to the scanning/sustain electrode lines has a main scanning pulse MSP with a width (Tad+Td=Ts) of the main data pulse MDP and the supplementary data pulse ADP, and a supplementary scanning pulse with a width (Tad=Tas) of the supplementary data pulse ADP.
At the end, the driving waveform provides an effect of a prolonged address discharge period because the address discharge is occurred for Tad+Td+Tad time period at the discharge cell the main data pulse MDP is supplied thereto, and can reduce the address time period as much as the scanning pulses Vs supplied to the scanning/sustain electrode line Y are overlapped with each other for a preset time period.
However, the address driving part that supplies both the main data pulse MDP and the supplementary data pulse ADP has an increased power consumption as the two data pulses MDP and ADP are generated, independently.